Method of shot-blasting coil springs



Feb. 15, 1944. w. H. WALLACE 2,341,674

METHOD OF SHOT-BLASTING COIL SPRINGS Fi led March 19, 1942 INVENTOR. MLL/AM M HLLHCE llllll' lll ATTORNEY-5 56.2 F/aa BY W W j to be shot-blasted;

j Fig. 2 is a'similar view showing a helical coil spring made from wire or stock of substantially tangular cross-section.

Patented Fe b- 1944 METHOD F sno'r-nms'rnve coma smmes g vviuiam rr. Wallace, ambit; Mich assignor to Eaton Manufacturing Company, Cleveland,

Ohio, acorp'oratio n of Ohio Application Mai-ch19, 1942. Serial 435,314

' t 7' Claims.

This invention-' relates to the shot-blasting of coil springs for increasing their usefuldiie and aims .to provide-a novel method by. which the v shot blasting.treatment canbe carriedoutlmore effectively than heretofore by moving the springs substantially --in the direction ot their longitu- I dinal axes and along a relatively-inclined path during theirpassage through the shot stream.

Another object of my invention is to provide a novel method forshot blasting coil springs'in which the" springs are moved substantially in i the direction of their longitudinal axes and along a relatively inclined path during a first passage through the shot stream and are then reversed 'end-for-end and passed through the shotstrea'm a second time. I Y

Asa further object m'yinvention aims to pro- ,vide anovel method for shot-blasting coil springs l3 and ll of the convolutions. method," hereinafterdescribed in detail, this deoperationsfdisclosed in my Patent No; 2,249, 17,

granted July 15, 1941,-cert'ain portions of the spring. surfaces may be only partially presented to the'shot' stream and may not receive adequate treatment. In the case of the spring H, I find that this istrue'of one or-both of the side faces By my novel ficiency is overcome and all portions of the spring surfaces receive adequate treatment including the" side faces and of springsmadeirom stock r of substantially rectangular cross-section m Figs. 3 and 4 I have illustrated one manher in which my novel method of shot-blasting the coil's'prlngs l0 may be carried out. As here shown,'the-gsprings ID are passed through a shot 1 stream 1 k5 by endwise or axial-movement and are made from 'wire or stock of rectangular crosssection in whichsuch sprin'gsare' passed through the shot stream in a manner to cause corresponding faces on one side of the spring convolutions to. reoeive'efi'ective shot-blast treatment and then reversing the springs end-'ior-end and passing them through-the shot stream a second time so that the otherside facesoifthe convolutions will be effectively treated; 4

Other objects and advantages of tion and accompanying' drawing, in which:

Fig. 1 is a side elevation of a helical coil spring rectangular cross-section. Fig. 3 is an end view thereof;

- th e inven I tion will be apparent from the following descripsimultaneously rotated about their axes, but instead oi moving th springs substantially horizontally through theishot stream, that is to say, in a direction substantially normal to the general direction or the shot stream, I cause the springs tobe moved 'along 'an inclined support so that the direction or-path of axial travel of the springs is inclined to the general direction )0! the shot stream. By moving the springs 10 through the shot stream in such a relatively inclined condition, it will-be observedthat'the sides l6 0! the convolutions will'be elevated relative to the sides l I! and will be more directly presentedto the shot stream whilethe springs travel ther'ethrough. -It

. I will be seenalso that the movement of the springs Fig'. 4 is a side view, somewhat diagrammatic."

illustratingthe shot-blasting" of coil-springs by -my method:

Fig. 5 is a sectional view. taken as indicated shot-blasting operation; and.

" by nne' 5-5 of Fig. was further illustrating the Fig; 6 is another diagrammatic view similar to that of Fig. '4'but'showing amodified arrangementfor carrying out my shot-blasting method. In Figs. 1 and 2 I show coil springs l0 and I I to which my novel shot blasting method may be applied. The spring I0 is a conventional helical coil .spring made irom round wire or stock and having a plurality of convolutions H. The spring Ii is similar to the spring IQ but has been made from wire or stock of substantially 'rec- I have observed that when eoilspr ings are shot blasted, as, for example, by the shot-blasting.

through the shotstream" in this relatively inclined condition will not prevent the shotiromv entering the spaces between adjacent convolutions and effectively reaching all portions of the inner'sui'faces of the convolutions. The circumferential outer surfaces of the convolutions are, 7 of course, exposed directly to the shot stream. l After the coilsprinszs.v II) have passed through the shot strea'mand all of its surfaces have been shot-blasted as above explained; with the exception that the sides I! 01' the convolutions have received a relatively smaller amount 01' treat ment, I reverse the springs end-for-end and again pass them through the shot stream in the relatively inclined condition. During this second passage through the shot stream, the sides ll of the convolutions will be relatively elevated and more directly presented to the shot stream ,and will now receive, efl'ective treatment.- At the completion of the second passage through the shot stream, all portions of the springs will have been effectively treated by the shot stream.

In passing the springs it through the shot stream 15, the springs may be advanced by a belt or conveyor l8, as shown in Figs. 4 and 5, having spaced fingers l9 which en age and propel the springs. The belt l8 may extend around pulleys 20 and 2|, one of which may be suitably driven.

The belt may travel between a pair of substantially parallel rollers 22 and 23 on which the springs rest during their passage through the shot stream. One or'both of the rollers is rotatably" driven so as to impart continuous rotation to the springs while they are passing through the shot stream. The shot stream l may be obtained from a suitably driven shot-throwing wheel 24 located above the belt and which may have its axis extend transversely to the direction of spring travel.

In Fig. 6 I show another arrangement for care,

rying out my method but in which the rollers and 26 are inclined to the horizontal at a relatively steeper angle than the rollers of Fig. ,4 and the axis of the shot-throwing wheel 21 extends inythe same general direction as the rollers 25 and 26. In other respects the apparatus of Fig. 6 and its manner of use aresimilar to what has been described above in connection withFigs. 4'

and 5.

It is important to note that the support for the springs as formed by the rollers 22 and 23 in- Fig. 4 and the rollers 25 and 26 in Fig. 6 extends in inclined relation to the horizontal. In other words, the springs are moved along the support preferably in a downhill direction, althoughthey path which is inclined relative to the general direction of movement of the shot stream and simultaneously rotating the springs.

2. The method" of shot-blasting coil springs which comprises passing the springs through a shot stream while the springs are being rotated, and then reversing the springs end-for-end and passing them through the shot stream a second time.

3. 'The method of shot-blasting coil springs which comprises passing the springs through a shot streamby moving them in the direction of their axes along a path which is inclined relative to th general direction of movement of the shot stream and simultaneously rotating the springs about their axes, and then reversing the springs A end-for-end and passing them through the shot stream a second time.

*4; The method of shot-blasting coil springs which comprises passing the springs through a shot stream by moving them in the direction of their axes-along a downwardly extending support which is inclined relative to the/general direc-' could be made to .travel in an uphill direction, and

at a suitable inclination tothe horizontal which causes the relatively elevated sides of the convolutions to be presented more directly tothe shot stream, as explained above. It will be understood, of course, that the angle of inclination of the pathof travel of the springs may be varied considerably depending upon the pitch of the springs, the cross-sectional shape of the wire or stock, and various other factors or characteristics. Although Figs. 4 and fi'show my method being carried out withsprings lo made from round wire orstock,v the same operations are applicable to springs made from stock of other cross-sectional shapes such as the spring I I which is made from wire of rectangular cross-section.

From the foregoing description and the accompanying drawing, it will now be readily understood that I.have provided a novel method for shot-blasting coil springs so that all portions of the springs, including both side faces of the convolutions, will receive, effective treatment by the shot-blastin stream. r

While I have illustrated and described my shotblasting method in more or less detail, it will be understood, of course, that'I intend my-invention to cover all modifications coming within the scope of the appended claims.

Having thus described my invention, I claim:

1.The method vof shot-blasting coil springs which comprises passing the springs through a.

shot stream by moving them endwise along a.

tionof movementof the shot stream and simultaneously rotating the springs about their axes, andthen reversing the. springs end-for-end and,

passing them in the same manner through the shot-stream a second time.

5. The method of shot-blasting coilsprings which comprises passing the springs through a shot stream by. moving them in thedirection of their axes along a path which is inclined rela-.

tive to the direction of the shot stream such; that one side face of each convolution will be presented to the shot stream and simultaneously rotating the springs about their axes, and then reversing the springs end-for-end and moving them along said relatively inclined path and through the shot stream a second time such that" theopposite side face of each convolution will be presented to the shot stream.

6. The method of shot-blasting coil springs. made of wire of rectangular cross-section which comprises passing the springs through a shot 1 stream by moving them endwise along a path; which is inclined to the directionjof the shot, stream such that corresponding side faces of the spring convolutions will be relatively elevated and presented to the shot stream and simultaneously rotating the springs about their axes, and then reversing the springs end-for-end and moving them 7 endwise alongsaid inclined path and through the shot stream a second time such that the other side faces of theconvolutions willbe relatively elevated and presented to the shot stream. v '7. The method of shot-blasting coil springs which comprises passing the springs through a shot stream by endwise movement of the springs while they are being rotated about their axes.

and thenreversing the springs end-for-end and similarly passing them through the shot stream a second time. V

WILLIAM rr. WALLACE. 

